Sewage treatment apparatus



Oct. 7, 1969 6.1.. wALLAcE`- SEWAGE TREATMENT APPARATUS v Filed Dec. '7,1966 NIK. haw /m l '[NVENTOR.

F 13.3, GoRqoN L Wou/rcs fwfzwl ffwxi United States Patent O 3,471,020SEWAGE TREATMENT APPARATUS Gordon L. Wallace, Indianapolis, Ind.,assigner, by mesne assignments, to Aquapure, Inc., Indianapolis, Ind., acorporation of Indiana Filed Dec. 7, 1966, Ser. No. 599,845 Int. Cl.B01d 1/24; F26b 3/20 U.S. Cl. 210-152 7 Claims ABSTRACT F THE DISCLOSUREThe apparatus disclosed is a small capacity sewage disposal device inwhich sewage is shredded and pumped from an accumulator chamber onto aheat transfer place and is moved across the heatedl plate. This oxidizesthe sludge and evaporates the water content of the sewage. iinll chambervents the steam and collects the residue This invention relatesgenerally to sewage treatment, and more particularly to apparatussuitable for the treatment of sewage.

There are numerous areas of the country where sanitary sewers arenonexistent, or economically inaccessible, and where soil conditionspreclude the use of septic tanks. In such areas, especially where thepopulation is sparse, for example in rural areas, the cost of installinga conventional sanitary sewer system and treatment plant is prohibitive.Much of the domestic Iwaste in these areas is being discharged intostreams, or into open ditches where it eventually finds its Way tolarger streams.

Although the volume of domestic waste from any one residence would notcreate a signiiicant stream pollution problem, unless the stream werequite small, the cumulative eifect of the domestic waste from even asmall number of residences can cause considerable pollution. Inaddition, where open ditches are used, noxious odors are given olf bythe decaying waste and the ditches provide ideal breeding areas formosquitos and other insect pests. The problem exists not only withregard to single domestic installations but also with regard to sewagedisposal units for industrial wastes, and block-size or subdivisionsizeinstallations. Disposal units of smaller size are characterized byrelatively high unit cost. The apparatus of the present invention, whilecapable of being economically built on a scale providing the relativelysmall capacity necessary for single, domestic installation, can also beincreased in capacity so as to enable the processing of wastes fromlarge industrial plants and from multipleunit or subdivision homegroupings.

It is therefore an object of this invention to provide an improvedsewage treatment apparatus for the treatment of domestic or industrialwaste. 1

It is a further object of this invention to provide an apparatussuitable for single residence use.

It is a still further object of this invention to provide an apparatusfor the treatment of domestic waste which is fully automatic inoperation.

A still further object of this invention is to provide an apparatuswhich is comparatively simple in operation, and can be readily servicedby a relatively unskilled person.

Yet another object of this invention is to provide an apparatus for thetreatment of domestic waste that is rugged and will operate many yearswithout major repairs.

These and other objects will become apparent as the description proceedswith reference to the accompanying drawings in which:

FIG. l is a side elevation of the apparatus partly in section.

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FIG. 2 is a top sectional view of the apparatus taken generally alongthe line 2-2 of FIG. 1.

FIG. 3 is a schematic diagram of a control circuit for the apparatus.

In the preferred embodiment of the present invention, the apparatus issubstantially enclosed in a generally inverted U-shaped housing 11 whichis internally partitioned into a sewage accumulator section 12, aheating and oxidizing section 13, and a ily ash collector section 14, asbest shown in FIG. 1.

The housing 11 has a top 17, end walls 18 and 19, side walls 21 and 22,a first bottom 23, a second bottom 24, center walls 26 and 27, andhorizontal closure plate 16, as best shown in FIGS. l and '2.

The sewage accumulator section 12 is enclosed by a portion of the top17, the end wall 18, a portion of the side wall 21, a portion of theside wall 22, the lirst bottom 23, and an internal partition 28. Theinternal partition 28 is aixed to the top 17, to the side wall 21 and tothe side wall 22, and extends downwardly from the top 17 and separatesthe accumulator section from the heating and oxidizing section. An inletopening 29 suitable for coupling to a tile or soil pipe admits se-Wageto the accumulator section 12.

Between the lower marg-in of the internal partition 28 and the bottom 23is the shredding means indicated generally at 31. The shredding means 31including a cylinder 32 having longitudinal vanes 33 inclined radiallyin the direction of rotation as indicated by the arrow 34. The cylinder32 is mounted on a shaft 36 which is journaled in suitable bearings 37mounted in the walls 21 and 22. The cylinder 32 and shaft 36 are rotatedin the direction of the arrow 34 by a belt 38 and pulley 39 mounted onthe shaft 36. A lip member 41 is atlixed to the bottom 23 and is inclose spaced relationship to the locus of the peripheral edges of thevanes 33. The lip member 41 which may be fabricated from angle iron, hasa concave surface 42 which cooperates with peripheries of the vanes 33to shred the sewage to form sludge. The vanes 33 cooperate with the lipmember 41 to impart hydraulic head to the sludge suflicient to force itupward through the column 46 in the heating and oxidizing section 13.

The heating and oxidizing section 13 is generally L- shaped, isrectangular in cross section, and is enclosed by a portion of the top17, a portion of the side Wall 21, a portion of the side wall 22, andthe heat transfer plate 48. One end of the heating and oxidizingsection, indicated at 49, receives sludge from the column 46. The otherend of the heating and oxidizing section is partially closed by thepartial closure member 51, which Will be described more fullysubsequently. A baie plate 40, hinged to the sidewall of column 46,permits ow into the section 13 but prevents any back-pressure reverseilow.

Within the heating and oxidizing section 13 are two shafts 52 and 53,oriented parallel to the shaft 36 of the shredding means and journaledin suitable bearings 54 mounted in the side walls 21 and 22. The shaft52 extends outwardly from the side Wall 21 and has a pulley 56 mountedthereon to accept the belt 57. Two pairs of sprockets 58 and 59 aremounted on the shafts 52 and 53. One sprocket of each pair is mounted oneach shaft as best shown in FIG. 2. An endless chain 61 is received uponthe iirst pair of sprockets 58 and an endless chain 62 is received uponthe other pair of sprockets 59. A plurality of scraper members 63 areaixed to alternate links of the chains 61 and 62 so that the scrapermembers 63 are at all times parallel to the shafts 52 and 53. The shafts52 and 53, the pairs of sprockets 58, and 59, the chains 61 and 62 areso arranged that when the shaft 52 is driven by the pulley 56 in thedirection of the arrow 64, the scraper members 63 scrape the heattransfer plate 48 to convey the sludge from left to right as viewed inFIG. l. This scraping action not only conveys the sludge, but also keepsthe heat transfer plate 48 substantially free of charred or caked sludgewhich has a very low coeillcient of heat transfer and if allowed toaccumulate on the heat transfer plate would substantially block the ilowof heat to the sludge. Heat is supplied to the heat transfer plate 48 bya heat source 47, preferably an electrical resistance heater asindicated in FIG. 3, mounted between the heat transfer plate 48 and thehorizontal closure plate 16.

As the sludge is scraped along the heat transfer plate 48 by the scrapermem-bers 63, it is dried and oxidized into ily ash. The steam formed bythis process creates a slight pressure within the heating and oxidizingsection. The steam cannot escape to the accumulator section because ofthe sludge in the column 46, and is forced to exhaust rightwardly asviewed in FIG. 1 through the opening 5l) above the partial closuremember 51. When the sludge and ily ash reach the right end of the heattransfer plate 48, as viewed in FIG. l, the partial closure member 51forces them upwardly and leftwardly. The ily ash is then carriedrightwardly by the ilow of steam through the opening 50 and the sl-udgenot oxidized to ily ash is carried leftwardly where it falls back to theheat transfer plate 48 and is eventually oxidized to ily ash.

The ily ash carried through the opening 50 by the steam falls out and iscollected in the ily ash collector section 14.

The fly ash collector section 14 is enclosed by the end wall 19, aportion of the side wall 21, a portion of the side wall 22, the bottom24, and the center wall 27. The ily ash collector section is providedwith a door 66 for the removal of accumulated ily ash.

The ily ash collector section 14 may be provided with an igniter 67 forigniting and burning any combustible gases given oif when the sludge isdried and oxidized and further provided with a pressure release safetyvalve 45. In the preferred embodiment an electrical spark igniter isused. There are two electrodes 68 and 69 insulatedly mounted to thesidewall 21 as shown in FIG. 2. Appropriate voltage for the electrodesis supplied by the transformer 71.

The ily ash collector section 14 is also provided with a vent 73 andsleeve 72 whereby the steam and burnt gases are discharged into theatmosphere. Suitable ducting 74 may be connected to the sleeve 72 inorder to carry the steam and burnt gases away from the location wherethe apparatus is installed.

Also mounted in the ily ash collector section 14 is a baille 76 whichaids separation of the ily ash from the ilow of steam and burnt gasescausing it to precipitate to the bottom of the ily ash collector sectionand not be carried to the atmosphere by the steam and burnt gases. Inthe preferred embodiment of the invention, the baille 76 is a singlebaille plate affixed to the wall 19 above the vent 73 and extendingdownwardly and away from the wall 19 and having its lower edge below thebottom of the vent 73. This configuration causes the steam and burntgases to ilow generally in the direction of the arrow 77. When the steamenters the ily ash collector section through the opening 50, it has arelatively high velocity and easily carries the ily ash with it into theily ash collector section. However, because of the large cross sectionalarea of the ily ash collector section, the velocity is greatlydecreased, causing the ily ash to precipitate. However, the velocityagain increases as the steam enters the vent 73, and were it not for thebaille 76, a considerable amount of ily ash would be carried into thevent 73 before it had reached the bottom of the ily ash collectorsection and would be Idischarged into the atmosphere. A filter, shownschematically at 75 in FIG. 1, may be provided in the outlet duct 74 totrap any residual ily ash which might be carried to the outlet duct.

Control means in the form of a iloat switch 81 may be provided in thesewage accumulator section 12 for controlling the operation of theshredding means and the heating means. It may also be desirable toinclude a thermostat 82 for control of the heat source 47 of the heatingmeans. In the preferred embodiment of the present invention, the iloatswitch 81 includes a iloat 83, supported on a rod 84 slidable within asleeve 85 mounted in the top 17. An electric switch 86 is operated bythe switch arms 87 mounted on the rod 84. The switch arms 87 are mountedto the rod 84 with set screws 88 and may be located higher or lower onthe rod 84 to provide the desired operation.

Y An electric motor 91 is mounted on the housing 11 as shown in FIG. 1,and, by means of belts 38 and 57, drives the shaft 36 of the shreddingmeans and shaft 52 of the heating means, respectively.

The heat source 47 may be either gas, electric or oil ilred. Similarly,a gasoline engine may be used instead of the electric motor 91. Thiswould be desirable in locations where electricity is not available. Inthe event a gasoline engine were used, the control means could take onmany forms such as hydraulic or pneumatic, and be used to control aclutch on the gas engine shaft or to control automatic starting andstopping of the gas engine in cooperation with a storage battery orcompressed air.

In operation, sewage ilows into the sewage accumulator section 12. Whenthe level of accumulated sewage reaches a predetermined depth, the iloatswitch 81 is actuated and turns on the shredding means and the heatingmeans. The shredding means 31 shreds the sewage to sludge and pumps itthrough the column 46 to the heating means where the scraper members 63rake the sludge over the heat transfer plate 48 which is heated by theheat source 47. The sludge is dried and oxidized by the heat transferredto it from the heat transfer plate 48 and gives off steam, carbondioxide, and some combustible gases. The steam and gases exit throughthe opening 50, carrying along the sludge which has been oxidized to ilyash. Sludge which has not been oxidized to ily ash is returned to theheat transfer plate 48 by the action of the scraper members 63 and thepartial closure member 51. The ily' ash is precipitated in the ily ashcollector section 14. Precipitation is aided by the baille 76. Thecombustible gases are ignited and burned by the igniter 67. Steam andburnt gases exit through the vent 73 and are discharged to theatmosphere.

It will be seen that the present invention provides an improved sewagetreatment apparatus suitable for the treatment of domestic sewage andwhich is suitable for single residence use. The operation is fullyautomatic, except for periodic removal of -ily ash from the apparatus.The apparatus is comparatively simple in construction and in operationand can be readily serviced by a relatively unskilled person. Further,the apparatus is rugged and will operate for great lengths of timewithout major repairs.

The invention claimed is:

1. Treatment apparatus for sewage comprising:

(a) accumulator means for accumulating sewage;

(b) .shredding means for receiving said sewage from said accumulatormeans and for shredding said sewage into sludge;

(c) heating means for receiving said sludge from said shredding means,raising the temperature of said sludge suiliciently to evaporate thewater content thereof thereby forming dried sludge and steam, andfurther raising the temperature of said dried sludge suillciently tooxidize said dried sludge to form ily ash; and

(d) separating and collecting means for receiving said steam and saidily ash from said heating means, separating said ily ash from saidsteam, collecting said ily ash and venting said steam to the atmosphere,

said heating means including a heat transfer plate, a heat source forheating said heat transfer plate, scraper members for scraping said heattransfer plate and for propelling said sludge across said heat transferplate, said heat transfer plate acting to transfer heat to said sludgethereby raising the temperature of said sludge.

2. The invention of claim 1 wherein said heating means includes a seconddriven shaft and a third shaft parallel to said first shaft and mountedfor rotation, two pairs of sprockets affixed in spaced relationship onsaid two shafts, one sprocket of each pair being mounted on each of saidtwo shafts, two endless chains, one of said chains being received uponone pair of said sprockets and the other chain being received upon theother pair of sprockets, said scraper members being aflixed to the linksof said two chains in parallel relationship such that when one of saidsecond driven shaft is rotated said scraper members will move across andscrape said heat transfer plate.

3. The invention of claim 2 wherein said shredding means includes avaned impeller mounted for rotation on a driven shaft, and a lip membermounted in close spaced relationship to said impeller, said impellerbeing cooperable with said lip member to receive said sewage from saidaccumulator means, to shred said sewage into sludge, and to impartsufficient hydraulic head to said sludge to convey said sludge to saidheating means.

4. The invention of claim 3 wherein said collecting and separating meansincludes a receptacle for collecting said fly ash, said receptaclehaving a vent for discharging said steam to the atmosphere and a doorfor removing accumulated y ash from said receptacle, a baflle plateaflixed within said receptacle and adapted to deect the flow of saidsteam and ily ash from passing directly through said receptacle to saidvent, thereby aiding the separating of said fly ash from said steam.

5. The invention of claim 3 further comprising drive means for drivingsaid first driven shaft and said second driven shaft.

`6. The invention of claim 5 further comprising control means includinga first electrical switch for turning on and turning off said drivemeans, said switch being responsive to the level of sewage in saidaccumulator means and acting to turn on said drive means at a rstpredetermined level and to turn off said drive means at a secondpredetermined level.

'7. The invention of claim 6 wherein said control means includes asecond electrical switch for turning on and turning off said heatsource, said switch being responsive to the temperature of said heattransfer plate and acting to turn on said heat source when thetemperature is below a rst predetermined value and to turn off said heatsource when said temperature is above a second predetermined value.

References Cited UNITED STATES PATENTS 1,329,727 2/1920 Smith 210--152 X2,094,909 10/1937 Baily et al. 210-152 X 2,330,542 9/1943 Barnebl et alZIO- 152 X 2,792,117 5/1957 Laboon 2.10-187 X JAMES L. DECESARE, PrimaryExaminer U.S. Cl. X.R. ZIO-121, 179, 526

